Centralized event streams

runtime/observatory/lib/src/elements/isolate_ref_wrapper.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:html';
-import 'dart:async';
 
 import 'package:observatory/app.dart';
-import 'package:observatory/models.dart' show IsolateUpdateEvent;
-import 'package:observatory/mocks.dart' show IsolateUpdateEventMock;
 import 'package:observatory/service_html.dart' show Isolate;
 import 'package:observatory/src/elements/isolate_ref.dart';
 import 'package:observatory/src/elements/helpers/tag.dart';
 import 'package:observatory/src/elements/shims/binding.dart';
 
 @bindable
 class IsolateRefElementWrapper extends HtmlElement {
 
   static const binder = const Binder<IsolateRefElementWrapper>(const {
       'ref': #ref
     });
 
   static const tag = const Tag<IsolateRefElementWrapper>('isolate-ref');
 
-  final StreamController<IsolateUpdateEvent> _updatesController =
-    new StreamController<IsolateUpdateEvent>();
-  Stream<IsolateUpdateEvent> _updates;
-  StreamSubscription _subscription;
+  Isolate _isolate;
 
-  Isolate _isolate;
   Isolate get ref => _isolate;
-  void set ref(Isolate ref) { _isolate = ref; _detached(); _attached(); }
+
+  void set ref(Isolate value) {
+    _isolate = value;
+    render();
+  }
 
   IsolateRefElementWrapper.created() : super.created() {
-    _updates = _updatesController.stream.asBroadcastStream();
     binder.registerCallback(this);
     createShadowRoot();
     render();
   }
 
   @override
   void attached() {
     super.attached();
-    _attached();
-  }
-
-  void _attached() {
-    if (ref != null) {
-      _subscription = ref.changes.listen((_) {
-        _updatesController.add(new IsolateUpdateEventMock(isolate: ref));
-      });
-    }
     render();
   }
 
-  @override
-  void detached() {
-    super.detached();
-    _detached();
-  }
-
-  void _detached() {
-    if (_subscription != null) {
-      _subscription.cancel();
-      _subscription = null;
-    }
-  }
-
   void render() {
     shadowRoot.children = [];
-    if (ref == null) return;
+    if (ref == null) {
+      return;
+    }
 
     shadowRoot.children = [
       new StyleElement()
         ..text = '''
         isolate-ref-wrapped > a[href]:hover {
             text-decoration: underline;
         }
         isolate-ref-wrapped > a[href] {
             color: #0489c3;
             text-decoration: none;
         }''',
-      new IsolateRefElement(_isolate, _updates,
-                                 queue: ObservatoryApplication.app.queue)
+      new IsolateRefElement(_isolate, app.events, queue: app.queue)
     ];
   }
+
+  ObservatoryApplication get app => ObservatoryApplication.app;
 }